PHYSIOLOGICAL STUDIES OF SOME HERBICIDES EFFECTS AT DIFFERENT FERTILIZATION LEVELS ON MAIZE (ZEA MAYS L.) GROWTH AND YIELDS

Abstract

Two field experiments were conducted at Agricultural Experiment and Research Station, Faculty of Agriculture, Cairo University at Giza, Egypt, during 1998 and 1999 summer seasons. The objective ofthis study was to investigate the effect of nitrogen fertilization levels, weed control treatments and their interaction on existing weed species distribution and densities, maize growth ,yields and chemical analyses of maize leaves and grains . A split randomized complete block design with four replicates was used . Main plots were randomly assigned to four levels of nitrogen (zero, 40, 80 and 120 kg/fed.), and sub plots included twelve weed control treatments at random as follows: 1- Unweeded check; 2- Hand weeding at 3 and 5 weeks after sowing

(WAS) ; 3- Cultivation once at 3 WAS ; 4- Cultivation twice at 3 and 5 WAS; 5- Fluroxypyr (20 g a.i./fed.) ; 6- Fluroxypyr (40 g a.i./fed.) ; 7- Pyridate (210 g a.i./fed.) 8-pyridate (420 g a.i./fed.); 9- Prosulfuron (8.4 g a.i./fed.) ; 10- Prosulfuron (16.8 g a.i./fed.) ; 11- Primisulfuron (8.4 g a.i./fed.) and 12- primisulfuron (16.8 g a.i./fed.). All herbicides were

applied post emergence . The experimental unit included 5 rows distanced at 70 em. a part and 3.0 m length, occupying an area of about 10.5 m2 • Maize hybrid SC-10 was sown at may 1 t11 and 25'11 in 1998 and

1999 seasons , respectively .